I have to make sure I have a clean Mac because I want to sell it to a friend of mine. I do a lot of work online and I don’t need my files sitting around because if they were to get stolen by anyone it could cost me a lot of money. When I get the Mac I have cleaned, I want to make sure that not a trace of anything I did before is left. Then I want help getting it back to factory settings so that who I sell it to has a clean slate to work with.